The loss of refrigerant such as R-12 refrigerant from refrigeration systems, particularly during servicing of automotive air conditioning systems is the subject of much public concern at this time. A refrigeration service mechanic in servicing the air conditioning system normally vents the same. During venting, a significant amount of R-12 vapor is lost from the air conditioning system. There is a need, therefore, to provide a practical, simple, effective and low cost refrigerant recovery and restoration system which will allow the mechanic to vent an automotive air conditioning system with full recovery of the vapor contained therein, to provide a system which at least in part is relatively transportable to the situs of the automotive or like air conditioning or refrigeration system, which produces reclaimed refrigerant of equal quality in comparison to virgin refrigerant which is small in size, but which will be capable of operating with the volume of normal automotive air conditioning service operation.
Attempts have been made to produce an effective refrigerant recovery and/or disposal, purification and recharging system. Issued U.S. Patents representative of such known systems are: U.S. Pat. Nos. 3,232,070; 4,285,206; 4,363,222; 4,441,330; 4,476,688; 4,539,817; 4,554,792; 4,646,527; and 4,766,733.
These patents disclose as aspects of such refrigerant recovery systems the employment of components such as vacuum pumps, oil separators, condensers, liquid refrigerant receivers and accumulators. Unfortunately, the systems identified above are characterized by complexity and high pressure operation and are plagued with maintenance problems due particularly to the high pressure portions of the system.
It is therefore an object of the present invention to provide an improved, low cost, simple, essentially atmospheric pressure operated refrigerant recovery and restoration system which operates primarily as a direct condensation process, which has particular application to servicing automotive air conditioning systems, but is not limited thereto, and which may be advantageously employed in servicing home refrigerators or systems using R-12 as refrigerant, and which obviates the problems discussed above with respect to the known prior art.
All of the prior attempts to recover refrigerant have suffered from the difficulty that they require extensive apparatus to be brought to the site where the refrigerant is to be salvaged, or that the refrigeration unit being serviced has to be brought to a central reclaiming system. The present invention, by its use of approximately atmospheric pressure, bags which may be either reusable or even disposable, permits a refrigeration service engineer to fill a number of the bags at various locations where refrigerant is to be salvaged and, for example, at the end of his working day, return these bags to a central refrigeration recovery system where the refrigerant may be condensed and purified for reuse.
Another method which was used in the past for recovering refrigerant was to fill small pressure vessels with the refrigerant by compressing the refrigerant into the pressure vessels through the action of the compressor on the refrigeration unit from which the refrigerant is being withdrawn or by action of a liquid pump or a vacuum pump. As anyone connected with liquified compresses gas handling knows, over-filling of any pressure vessel is always of concern. Pressure relief devices are not always reliable and may fail to open after years of hard handling in and out of trucks, contamination by grease and oil, corrosion, etc. Therefore, the possibility of hydrostatic rupture and even explosion is always present when a pressure vessel is being filled. This danger is greatly extenuated when the filling is being done in the field under adverse circumstances and generally without any weighing device, often by only modestly experienced personnel.
It is an object of the present invention to provide a safe, low cost, simple, essentially atmospheric pressure refrigerant recovery system which avoids the need for bringing expensive, bulky equipment to the location from which the refrigerant is to be salvaged. Another object is to provide a reclaiming system which is light and small which can be brought to the salvage site. Still another object is to avoid having a mechanical reclaiming system for each service mechanic or for small companies which may not be able to justify the purchase of reclaiming systems. Still another object is to avoid the difficulty of smaller reclaiming systems which may take too long to recover the refrigerant vapor which is being salvaged. A further object is to provide a simple, easy to use, lightweight system to capture refrigerant vapor at the service site; to allow reclaiming at a later time without delaying the service work; and to allow a central reclaiming unit to reclaim refrigerant form a multiplicity of service men each servicing a multiplicity of refrigeration units. Another object is to avoid loss of CFC vapor to the atmosphere by making practical reclaiming of vapor from scrapped or disabled refrigerators and other refrigeration systems or those requiring servicing.
The present invention provides economic, convenience, and safety advantages over the solutions taught in the prior art because the bags used by the present invention are cheap and disposable or reusable, the bags take up virtually no space prior to their being filled, and the bags, if somehow overfilled, will merely rupture softly by tearing apart at the weld or elsewhere, without any danger of explosion due to high pressure rupture such as would be involved in the failure of a pressure vessel.